Patient{3 s chair

ABSTRACT

A chair intended for doctor&#39;&#39;s patients which is provided with a first electric motor and screw drive power unit, a linkage assembly for raising and lowering the chair, and a second electric motor and screw drive power unit including a linkage and cam assembly for tilting and horizontally extending the chair; an auxiliary linkage is provided which retracts a footrest as the chair assumes its lower position to avoid being hit by the patient&#39;&#39;s or doctor&#39;&#39;s foot or ankle.

United States Patent [72] Inventor Guenter A. Grams Costa Mesa, Calif. [21] Appl. No. 824,819 [22] Filed May 15. 1969 [45] Patented Aug. 3, 1971 [73] Assignee Surgical Mechanical Research, llnc.

Newport Beach, Calii.

[54] PATIENTS CHAIR 13 Claims, 10 Drawing Figs.

[52] 11.8. C1. 297/711, 297/330, 297/347 [51] Int. Cl. A47c1/04 [50] Field of Search 297/71, 80, 70, 330, 347, 348; 248/421 [56] References Cited UNITED STATES PATENTS 875,885 1/1908 Beminghaus 297/80 Peller 248/421 l-leyl, Jr. et al 297/330 X Ehrke et al. 297/71 X Svaerd 297/71 Fritz et al.... 297/330 X Church 297/330 X Primary Examiner-James T. McCall Attorney-Lyon & Lyon ABSTRACT: A chair intended for doctors patients which is provided with a first electric motor and screw drive power unit, a linkage assembly for raising and lowering the chair, and a second electric motor and screw drive power unit including a linkage and cam assembly for tilting :and horizontally extending the chair; an auxiliary linkage is provided which retracts a footrest as the chair assumes its lower position to avoid being hit by the patients or doctors foot or ankle.

PATENTEB Am; 3 s91:

SHEET 3 BF 3 FIE/0 INVENTOR. um/r55 A. GAE/1M5 Ame/v55 PATIENTS CHAIR BACKGROUND OF THE INVENTION Patient's chairs usually involve a hydraulic power unit, which may be operated manually or by motor-pump unit, for raising and lowering the chair while the tilting action is usually accomplished manually. Such chairs are usually bulky. In the examination or treatment of the eyes, ears, nose and throat, close approach to the patient by the doctor either directly or by instrument is required. For example, microscopes or similar image enlarging devices must be brought close to the patient; in testing the eyes, elaborate apparatus must be brought in front of the face. Often the doctor is forced to lean over the chair, assuming a tiring and unstable position in order to perform an examination or treat the patient. Of special annoyance is the footrest; which, when the chair is at its lowest position, actually is not needed, and often results in injury to the ankle of the patient or doctor.

SUMMARY OF THE INVENTION The present invention is directed to a patients chair particularly intended for use by doctors specializing in treatment of the eye, ear, nose and throat, or by dentists, and which is summarized in the following objects:

First, to provide a patients chair which while fully supporting the patient in a sitting or a reclined position is compact so that the doctor can approach closer to the patient without discomfort, and utilize instruments for close inspection that have heretofore been awkward or difficult to use.

Second, to provide a patients chair wherein the footrest is retracted under the chair when the chair is in its lowermost position so that a patient may seat himself as easily as he would in a conventional dining chair; further by reason of the retracted position of the footrest, and the chair being rotatably mounted, the doctor may readily rotate the chair from side to side without danger of injury by the footrest.

Third, to provide a patients chair which utilizes a novel electromechanical drive unit and lever assembly which raises and lowers the chair, and in raising the chair to the height that a footrest is needed, moves the footrest into position; further, the drive unit and lever assembly, although occupying a compact retracted position permitting examination or treatment while the doctor is seated, is capable of stable extension to permit the doctor to stand.

Fourth, to provide a patients chair which utilizes a novel electromechanical drive unit and lever-cam assembly which tilts the patient between a seated position and an essentially horizontal position.

Fifth, to provide a patients chair which permits use of a simple single handle control switch to move the chair vertically or to tilt the chair either selectively or simultaneously so that the patient can be moved quickly to the desired position.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of the patients chair, the chair being shown in its lowermost position and tilted upright to receive a patient in a sitting position, portions of the chair being broken away to illustrate internal mechanism.

FIG. 2 is a fragmentary, partial elevational view, partial sectional view, the sectional portions being taken in a plane parallel with .FIG. 1, showing the patiets chair in an intermediate raised position, and tilted to receive a patient in a sitting position.

FIG. 3 is a fragmentary side elevational view of the patients chair, taken from the same aspect as FIGS. 1 and 2, but showing the chair in its extreme raised position, and tilted to receive a patient in a reclined position.

FIG. 4 is a fragmentary sectional view, taken through 4-4 of FIG. 3.

FIG. 5 is a fragmentary sectional view, taken through 5-5 of FIG. 3.

FIG. 6 is a sectional view, taken through 66 of FIG. 3.

FIG. 7 is an enlarged fragmentary sectional view, taken through 7-7 of FIG. 3.

FIG. 8 is an enlarged fragmentary sectional view, taken through 8-8 of FIG. 1, with the gear motor units omitted, as well as the base portion of the chair.

FIG. 9 is a sectional view, taken through 9-9 of FIG. 2.

FIG. 10 is a wiring diagram, illustrating the manner in which the gear motors are electrically connected to a control switch.

The patients chair includes a fixed base member 1, which is preferably circular, and supports a rotatable base structure 2, which is also circular. Interposed between the base member I and base structure 2 is a relatively large thrust bearing 3. A central bolt 4 extends downwardly through the base structure 2 and screw threads into the fixed base member 1. A thrust bearing 5 underlies the head of the bolt 4i.

The base structure 2 is provided with a raised rectangular portion 6, having a pair of side flanges 7 which extend for wardly and rearwardly with respect to the chair which is mounted thereon. The side flanges define near their forward extremities an axis passing in or near a plane passing through the center of the base member 1. A pair of forward struts 8 are pivotally connected to the side flanges by pivotal connectors 9. Also, the forward struts are joined together by a web 10. Also, pivotally connected to the side flanges 7 by pivot connectors 9, is a pair of rearward struts Ill.

Each pivot connector 9 includes a shaft 12, having a screwthreaded portion and a slightly larger journal portion. The journal portion receives a flanged bushing 13. The shaft may screw directly into the member in which it is received, or may extends therethrough and receive a nut. The pivot connector is used not only for the struts 8 and 11, but is used, or modifications thereof are used, to fasten other pivotally connected parts of the patients chair.

The upper extremities of the forward struts 8 and rearward struts 11 are joined by pivot connectors 9 to a pair of upper struts 14. These struts are joined by a connecting web 15. Below their connections to the upper struts 14, the forward struts 8 are joined by pivot connectors 9 to lower struts 16.

A carrier 17 is provided which includes side flanges 18, joined by a crossweb 19 at their forward portions. The side flanges 18 are joined by pivot connectors 9 to the extremities of the upper struts l4 and the lower struts 16. The various connections provided between the struts 8, I1, 14, and 16, and with the side flanges 7 of the base structure 2 and the side flanges 18 of the carrier 117, are so located and the relative lengths of the struts are so proportioned that the carrier 17 remains essentially horizontal or parallel to the base structure as it moves from the position shown in FIG. I to the position shown in FIG. 3. Also, it will be noted, that the upper struts l4 and lower struts l6 occupy an essentially horizontal position when the carrier 17 is in its lower position, and an upwardly and rearwardly directed angular position when the carrier 17 is raised, as shown in FIG. 3.

Joined by pivot connectors 9 to the side flanges 18 of the carrier 17 is a pair of seat-supporting levers 20, joined by connecting webs 21. The major portions of the seat-supporting levers 20 are secured to the underside of a seat member 22. The portions of the levers 20 between the seat member and their connections with the carrier I7 slope downwardly and rearwardly from the seat member.

Near the rearward margin of the seat member 22, a pair of back-supporting levers 23 are joined by pivot connectors 9 to the seat-supporting levers 20. The back-supporting levers 23 are joined together by a connecting web 24. A back member 25 is secured to the levers 23. The lower edge of the back member terminates adjacent, but clear of, the rear edge of the seat member 22. Below the back member, the levers 23 form open or semilooped ends 26 which clear the rear web 21 connecting the seat-supporting levers 20. The underside ofone of the looped ends 26 is extended downward and curved to form a cam 27, which rides on a cam roller 28 supported from the crossweb 19 of the carrier 17. As will be brought out later, the cam 27 serves to tilt the seat-supporting levers 20 upwardly as the back-supporting levers 23 move toward a horizontal position.

The upper struts l4 and lower struts 16 are moved relative to the forward struts 8 and rearward struts 11 by a lower power unit 29. The power unit 29 includes a gear-motor 30, including speed reduction gears, not shown, which rotate a screw shaft 31. The gear-motor is provided with a downward extension 32, having a transverse bore which receives a pivot pin 33. The extension 32 is received in a recess provided in the base structure 2 and the pivot pin extends horizontally into the base structure so as to traverse the recess and pivotally support the extension 32. The screw shaft 31 extends upwardly from the gear-motor and receives a traveler sleeve 34, the upper end of which projects beyond the screw shaft and through an accommodation opening provided in the connecting web joining the upper struts 14. The upper end of the traveler sleeve receives a cross pin 35, the ends of which are received in mounting block 36 secured to the connecting web 15. The traveler sleeve 34 is provided with a collar 37 and a counterbalance spring 38 is mounted between the collar 37 and the upper end of the gear-motor 30. When the lower power unit 29 is retracted, the struts are moved to their lower positions, as shown in FIG. I, and when the power unit is extended, the struts assume the relative positions shown in FIG. 3.

An upper'power unit 39 is employed to tilt the seat and back of the chair. The upper power unit is essentially the same as the lower power unit except that no counterbalance spring 38 is employed. The gear-motor 30 of the upper power unit is provided with a mounting plate 40, having journal brackets which are joined to mating brackets extending from the crossweb 19 be means of pins 41. The traveler sleeve 34 of the upper power unit extends through an accommodation opening provided in the rearward connecting web 21 of the seat supporting levers 20, and the web is provided with a depending boss which receives a pivot pin 42 extending through the traveler sleeve.

In order to limit movement of the seat to an essentially horizontal position, when intended to receive a person in a seated position, a pair of adjustable stops 43 extend upwardly from the crossweb 19 of the carrier 17. An additional pair of adjustable stops 44 may extend between the web 15 connecting the upper struts 14.

A pair of leg-supporting levers 45 are joined to the forward extremities of the seat-supporting levers by means of pivot connectors 9. The lower extremities of the leg-supporting levers are joined by other pivot connectors 9 to brackets extending from a footrest 46, in the form of a rectangular plate. Also connected between the seat-supporting levers 20 and the footrest 46 is a bar 47. The pivotal connections at the ends of the bar'47 are spaced substantially equal distant from the pivot connectors at the extremities of the leg-supporting levers 45 so that the surface of the footrest 46 tends to remain in parallel relation with the seat member 22. A leg-supporting member 48 is secured to the leg-supporting levers 45.

It is desirable that the footrest 46 be retracted under the seat member 22 when the chair is in its lower position and tilted to support a patient in an upright or or seated position, as illustrated in FIG. I. This is accomplished by a footrest control mechanism 49, which includes a lever 50, pivotally connected to one of the semilooped ends 26, preferably the looped end having the cam 27. The lever 50 is joined by a clevis 51 to a shaft 52, which in turn, is connected to a pivot bracket 53 secured to one of the leg-supporting levers 45. It is desirable that a biasing force be applied to the connection between the lever 50 and the clevis 51. For purposes of illustration, this is shown in FIG. 8 as a torsion spring 54. However, a similar biasing force may be applied to the lever 50 by an appropriately located tension or compression spring.

Extending downwardly from the extremity of the lever 50 is a still thrust spring 55, having at its extremity an end disk 56, which as the chair moves from the position shown in FIG. 2 to the position shown in FIG. 1, engages the connecting web 15 between the upper struts I4. 7

The two motors of the two power units 29 and 39 are conventional reversible motors which are operated by a control switch 57. Preferably the control switch involves a toggle handle capable of universal movement so that by movement in one plane, one motor is turned in one direction or the other; whereas, movement in the plane at right angles thereto operates the other motor in either direction. Further, by compound movement, both motors may be operated simultaneously, an essentially conventional circuit by which this is accomplished, is indicated in FIG. 10.

In order to control rotation of the chair, a friction locking means 58 is provided. The locking means includes a'shaft 59 extending through the base structure 2. Secured to each end of the shaft byits midportion is a foot lever 60 having at its extremities foot-engageable pads 61. Extending downwardly from the central portion of the foot lever, below the shaft 59, is a friction member 62 which, when the foot lever is in the position shown in FIG. 1 bears against the fixed base member 1 to secure the chair against rotation. When the foot lever is tilted as shown in FIG. 3, the friction member 62 clears the fixed base member to permit rotation. Suitable stops 63 limit movement of the locking means.

Operation of the patients chair is as follows:

When the chair is retracted to its lowermost position, by the power unit 29, and the power unit 39 has moved the seat member 22 to a horizontal position, and the back member 25 to an upright position, the chair is adjusted to receive a patient in a sitting position, as shown in FIG. 1. In addition, the footrest 46 has, by operation of the footrest control mechanism 49, been retracted so that a patient in being seated in the chair need not step upon the footrest; in fact, the patient may seat himself in much the same manner as he would in order to occupy a conventional dining chair.

The retracted position of the footrest when the chair is in its lower position shown in FIG. 1, permits the doctor to be seated close to the patient, and yet permits the doctor to rotate the chair in the course of his examination or treatment without danger of being struck by the footrest.

As the power unit 29 is operated to raise the chair, the control mechanism 49 urges the footrest 46 forward so that as the chair reaches a height in which the footrest is needed, the footrest is moved forward to support the patients feet.

Irrespective of the height position of the chair, the chair may be tilted between the position shown in FIG. 1 or 2 and the position shown in FIG. 3. This is accomplished by the upper power unit 39. It will be seen that the back member 25 moves to an essentially horizontal position; the seat member is inclined; and the leg-supporting member 48 forms an obtuse angle with respect to the seat member, and similarly, the footrest 46 forms an obtuse angle with the leg-supporting member.

It should be noted that conventional limit switches, not shown, are provided within the gear-motor housing to determine the extreme movements of each power unit.

It should be further noted that for purposes of illustration, the seat member 22, back member 25 and leg-supporting member 48 are shown free of padding or cushions. However, in practice, these members are provided with suitable padding or cushions.

Still further, it should be noted that an appropriate housing is supported from the base structure or other appropriate part of the chair.

It should also be noted that in actual use, the chair is provided with appropriate armrests, not shown, which may vary depending upon the use intended of the chair.

While particular embodiments of this invention have been shown and described, it is not intended to limit the same to the details of the constructions set forth, but instead, the invention embraces such changes, modifications and equivalents of the various parts and their relationships as come within the purview of the appended claims.

Iclaim:

l. A patients chair, comprising: a. a base structure;

b. a seat structure;

a s ew and linkage connected to said leg support and extending under said seat structure, said linkage being operatively connected to said raising and lowering means when said seat structure approaches its lower position to draw said footrest and leg support into said space under said seat structure. A patient's chair, as defined in claim ll, wherein:

. said seat structure includes a seat and back, and means for tilting said seat and back between a position receiving a patient in an upright seated position and a position receiving a patient in an upright seated position and a position receiving a patient in a reclined position;

. said linkage having a connection, in addition to its connection with said raising and lowering means, with said tiling means for moving said leg support and footrest between a position receiving a patient in an upright seated position and a position receiving a patient in a reclined position.

A patients chair, comprising:

a base structure;

. a chairseathaving a back margin and a front margin;

a lower. strut means pivotally connected to said base structure and extending upwardly and forwardly therefrom;

.an upper. strut means pivotally connected to said chair seat at the back margin thereof;

. means, pivotally connecting said lower and upper strut means for movement between a folded position'in which said upper strutmeans extends forward and underlies said chair seatand said upper and lower strut means converge forwardly at a lesser angle and an extended position in which saidupper and lower strut means converge forwardly at a greater angle;

. and longitudinally extensibleand retractable means for moving said upper and lower strut means between their folded position and their extended position.

. A patients chair, as defined in claim 3, wherein:

. a leg. support depends from the front margin of said chair seat;

a foot support extends forwardlyfrom said leg support;

. and means are provided to retract said footrest under said chair seat with said leg support contiguous to said lower strut means when said upper and lower strut means are in their folded position.

. A patient's chair, as defined in claim 3, wherein:

. said upper and lower strut means include linkage operable to maintain, said chair seat in predetermined angular relation withsaid base structure as said strut means move between their extended and folded position. A patients chair, as defined in claim 3, which further comprises:

a. a back .and head-supporting means pivotally connected with the back marginof said chair seat; a leg support pivotally connected with the front margin of said chair seat; a foot support pivotally connected with said leg support;

and extensible and retractable means, interconnecting said chair seat and supporting means to effect movement between t a position supporting a person in a seated upright position and an inclined position. A patient's chair, comprising:

a fixed basemember; a rotatable base structure mounted thereon; a lower forward pair of struts and a lower rearward pair of struts pivotally mounted on said base structure, the members of each pair of struts being laterally spaced from each other and directed upwardly;

. an upper bottom pair of struts and an upper top pair of struts, the members of each pair of struts being laterally spaced from each other; each of the top pair of struts being pivotally connected to both the corresponding forward and rearward struts; and each of the bottom struts being pivotally connected to the corresponding forward strut; said upper struts extending rearwardly from the lower struts;

. a carrier structure pivotally connected to the upper struts;

. an extension and retraction means pivotally connected between said base structure and said top struts to raise and lower said carrier structure, the pivotal connections between said struts, base structure and carrier being so related that said carrier structure moves vertically essentially free of tilting movement;

. and a seat structure mounted on said carrier.

A patients chair, as defined in 7, wherein:

. said extension and retraction means includes a reversible motor, a jackscrew and traveler sleeve, and a weightcompensating spring urging said carrier toward its extended position.

9. A patients chair, as defined in claim 7, wherein said seat structure further comprises:

a. a seat frame pivotally connected to said carrier;

b. a back frame pivotally connected to said seat frame;

c. cam and roller means incorporating said back frame and said carrier;

d. and thrust and retraction means connected to said seat frame and to said carrier to effect tilting movement of said seat frame and said back frame.

10. A patients chair, as defined in claim 9, wherein said seat structure still further comprises:

a. a leg support pivotally connected to said seat frame;

b. a foot support pivotally connected to said leg support;

c. and linkage extending between said leg support and said back frame operable on tilting said seat structure to extend and retract said leg and foot supports.

llll. A patients chair, comprising:

a. a seat structure;

b. raising and lowering means including lower and upper sets of pivotally connected struts having a lower position wherein the lower set of struts slope upwardly and forwardly toward the front of the seat structure to define a recess thereunder;

. a leg support pivotally depending from the front of said seat structure;

. a footrest pivotally connected with said leg support;

. and linkage connected to said leg support and extending under said seat structure, said linkage being operatively connected to said raising and lowering means when said seat structure approaches its lower position to draw said footrest and leg support into said recess and under said seat structure.

12. A patients chair, comprising:

A. a seat structure;

B. a leg support pivotally connected to the seat structure;

C. a footrest pivotally connected to the leg support;

D. a first linkage extending between. the footrest and seat structure for maintaining the footrest in essentially parallel relation to the seat structure;

E. a second linkage extending from the leg support under the seat structure for pivoting the leg support forwardly and rearwardly;

F. and means for raising and lowering the seat structure, en

gageable with the second linkage, as the seat structure approaches its lower position, to pivot the leg support and retract the footrest under the seat structure.

113. A patients chair, as defined in claim 12, which further comprises:

a. a backrest pivotally connected to the seat structure;

b. means connected to the backrest and seat for tilting the backrest between an essentially vertical position and an essentially horizontal position and for tilting the seat structure between an essentially horizontal position and 

1. A patient''s chair, comprising: a. a base structure; b. a seat structure; c. raising and lowering means connected to the base structure and the back side of the seat structure, said means, when in its lower position, forming a space under the forward portion of the seat structure and above the base structure; d. a leg support pivotally depending from the front of said seat structure; e. a footrest pivotally connected with said leg support; f. and linkage connected to said leg support and extending under said seat structure, said linkage being operatively connected to said raising and lowering means when said seat structure approaches its lower position to draw said footrest and leg support into said space under said seat structure.
 2. A patient''s chair, as defined in claim 1, wherein: a. said seat structure includes a seat and back, and means for tilting said seat and back between a position receiving a patient in an upright seated position and a position receiving a patient in an upright seated position and a position receiving a patient in a reclined position; b. said linkage having a connection, in addition to its connection with said raising and lowering means, with said tiling means for moving said leg support and footrest between a position receiving a patient in an upright seated position and a position receiving a patient in a reclined position.
 3. A patient''s chair, comprising: a. a base structure; b. a chair seat having a back margin and a front margin; c. a lower strut means pivotally connected to said base structure and extending upwardly and forwardly therefrom; d. an upper strut means pivotally connected to said chair seat at the back margin thereof; e. means pivotally connecting said lower and upper strut means for movement between a folded position in which said upper strut means extends forward and underlies said chair seat and said upper and lower strut means converge forwardly at a lesser angle and an extended position in which said upper and lower strut means converge forwardly at a greater angle; f. and longitudinally extensible and retractable means for moving said upper and lower strut means between their folded position and their extended position.
 4. A patient''s chair, as defined in claim 3, wherein: a. a leg support depends from the front margin of said chAir seat; b. a foot support extends forwardly from said leg support; c. and means are provided to retract said footrest under said chair seat with said leg support contiguous to said lower strut means when said upper and lower strut means are in their folded position.
 5. A patient''s chair, as defined in claim 3, wherein: a. said upper and lower strut means include linkage operable to maintain said chair seat in predetermined angular relation with said base structure as said strut means move between their extended and folded position.
 6. A patient''s chair, as defined in claim 3, which further comprises: a. a back and head-supporting means pivotally connected with the back margin of said chair seat; b. a leg support pivotally connected with the front margin of said chair seat; c. a foot support pivotally connected with said leg support; d. and extensible and retractable means, interconnecting said chair seat and supporting means to effect movement between a position supporting a person in a seated upright position and an inclined position.
 7. A patient''s chair, comprising: a. a fixed base member; b. a rotatable base structure mounted thereon; c. a lower forward pair of struts and a lower rearward pair of struts pivotally mounted on said base structure, the members of each pair of struts being laterally spaced from each other and directed upwardly; d. an upper bottom pair of struts and an upper top pair of struts, the members of each pair of struts being laterally spaced from each other; each of the top pair of struts being pivotally connected to both the corresponding forward and rearward struts; and each of the bottom struts being pivotally connected to the corresponding forward strut; said upper struts extending rearwardly from the lower struts; e. a carrier structure pivotally connected to the upper struts; f. an extension and retraction means pivotally connected between said base structure and said top struts to raise and lower said carrier structure, the pivotal connections between said struts, base structure and carrier being so related that said carrier structure moves vertically essentially free of tilting movement; g. and a seat structure mounted on said carrier.
 8. A patient''s chair, as defined in 7, wherein: a. said extension and retraction means includes a reversible motor, a jackscrew and traveler sleeve, and a weight-compensating spring urging said carrier toward its extended position.
 9. A patient''s chair, as defined in claim 7, wherein said seat structure further comprises: a. a seat frame pivotally connected to said carrier; b. a back frame pivotally connected to said seat frame; c. cam and roller means incorporating said back frame and said carrier; d. and thrust and retraction means connected to said seat frame and to said carrier to effect tilting movement of said seat frame and said back frame.
 10. A patient''s chair, as defined in claim 9, wherein said seat structure still further comprises: a. a leg support pivotally connected to said seat frame; b. a foot support pivotally connected to said leg support; c. and linkage extending between said leg support and said back frame operable on tilting said seat structure to extend and retract said leg and foot supports.
 11. A patient''s chair, comprising: a. a seat structure; b. raising and lowering means including lower and upper sets of pivotally connected struts having a lower position wherein the lower set of struts slope upwardly and forwardly toward the front of the seat structure to define a recess thereunder; c. a leg support pivotally depending from the front of said seat structure; d. a footrest pivotally connected with said leg support; e. and linkage connected to said leg support and extending under said seat structure, said linkage being operatively connected to said raising and lowering means when said seat structure appRoaches its lower position to draw said footrest and leg support into said recess and under said seat structure.
 12. A patient''s chair, comprising: A. a seat structure; B. a leg support pivotally connected to the seat structure; C. a footrest pivotally connected to the leg support; D. a first linkage extending between the footrest and seat structure for maintaining the footrest in essentially parallel relation to the seat structure; E. a second linkage extending from the leg support under the seat structure for pivoting the leg support forwardly and rearwardly; F. and means for raising and lowering the seat structure, engageable with the second linkage, as the seat structure approaches its lower position, to pivot the leg support and retract the footrest under the seat structure.
 13. A patient''s chair, as defined in claim 12, which further comprises: a. a backrest pivotally connected to the seat structure; b. means connected to the backrest and seat for tilting the backrest between an essentially vertical position and an essentially horizontal position and for tilting the seat structure between an essentially horizontal position and an inclined position; c. said tilting means being engageable with the second linkage to pivot the leg support forwardly with respect to the seat structure. 